Radioactive radiation counter tube with improved high temperature properties



May 1969 s. M. PERELMAN ET AL 3*444'376 RADIOACTIVE RADIATION COUNTER TUBE WITH IMPROVED HIGH TEMPERATURE PROPERTIES Filed June 1, 1965 US. Cl. 250-836 2 Claims ABSTRACT OF THE DISCLOSURE Radiation counter tube including elements with a work function of 3.5 electron-volts at operating temperature and separators having a TK-lOO minimum of 475 C. and an envelope of 54% SiO 18.5 A1 13.5% CaO, 8% BaO and 6% ZnO.

The present invention relates to gaseous discharge counter tubes operating at high temperatures and used for registering radioactive radiation.

There are known gaseous discharge counter tubes operating in the range of positive temperatures up to 200 C.

An object of the present invention is to provide a radio active radiation counter which is able to operate at high temperatures of the order of 200 to 350 C. and over, said counter having improved electrical characteristics and longer service life as compared with the known ones.

This object is achieved by the -fact the design components of the counter are made of materials having a work function of at least 3.5 electron-volts at the operating temperature and the inner separating elements having TK-lOO not less than 475 C. (where TKl00* is the temperature at which the resistivity of materials is equal to 10 ohms/cm.). As one of the materials meeting the above mentioned requirements, there is preferably used glass of the following composition: SiO --54%; A1 O 18.5%; CaO-13.5%; BaO8%; ZnO6%.

In particular, the invention makes it possible to perform logging works in deeper high-temperature wells as well as to create counting equipment without an auxiliary cooling system. This enables to considerably simplify the counting and measuring equipment, to decrease its overall dimensions, weight and power consumption.

The invention will further be described in connection with an exemplary embodiment thereof.

The accompanying drawing is a cross-sectional view of a counter tube of the invention.

The counter comprises gas-filled envelope 1, anode 2, cathode 3, field-forming tube 4, internal lead-out of stem nited States Patent 3,444,376 Patented May 13, 1969 Percent SiO 54 A1 0 18.5 CaO 13.5 BaO 8 ZnO 6 The melting point of the glass is 820 C. The linear expansion coeflicient is equal to (49i2) 10 deg.

What is claimed is:

1. A radioactive radiation counter tube comprising in operative association elements of material having a work function of at least 3.5 electron-volts at operating temperature, separating elements having a TK-l00 minimum of 475 C., and an envelope housing said elements, said separating elements and envelope being of glass having, at 200 C. and higher, a work function of at least 3.5 electron-volts and a TK-lOO of at least 475 C., said glass being of about the following composition:

2. A radioactive radiation counter tube comprising in operative association elements of material having a Work function of at least 3.5 electron-volts at operating temperature, separating elements having a TK-100 minimum of 475 C., and an envelope housing said elements, said separating elements and envelope being of glass having, at 200 C. and higher, a work function of at least 3.5 electron volts and a TK-l00 of at least 475 C.

U.S. Cl. X.R. 106-52: 31393 

